Electric switch



Aug. 1, 1950 M. R. SWINEHART ELECTRIC SWITCH Filed Dec. 6, 1945 rim Aug. 1, 1950 UNITED ELECTRIC SWITCH Merle R. Swinehart, Milwaukee, Wis., aasignor to Cutler-Hammer, Inc., Milwaukee, Win, a

corporation of Delaware Application December 8, 1945, Serial No. 633,112

4 Claims. (01. zoo-m) This invention relates to antibounce contact mechanisms for electric switches.

The invention has among its objects to provide an improved contact mechanism for electric switches which operatm to frictionally dissipate the kinetic energy present in the moving switch parts when the same are moved into circuit closing position to thereby minimize separation of the switch contacts by rebound after they have once engaged.

Another object is to provide an antibounce contact mechanism of the aforesaid character which is simple and rugged in construction, positive and reliable in operation and which is capable of being readily applied to existing control switches of various types and particularly spring closed electromagnetically operated switches.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates an embodiment of the invention which will now be described, it being understood that various modifications may be made in the embodiment illustrated without departing from the spirit and scope of the appended claims.

In the drawing,

Figure 1 is a side elevational view of an electromagnetic switch embodying the invention;

Fig. 2 is a fragmentary end elevational view of switch shown in Fig. 1 illustrating one of the contact mechanisms thereof;

Fig. 3 is a front elevational view of the contact finger and operating armature shown in Fig. 1, and

Fig. 4 is a sectional view on line 4-4 of Fig. 3.

Referring to Fig. 1, a contact mechanism embodying the invention is shown in connection with an electromagnetic switch of the type disclosed in the patent to C. Stansbury et 9.1., No.

2,205,676, issued June 25, 1940. Briefly described this switch is provided with an operating coil i having a center core member 2 which is mounted midway between the side arms of a U-shaped. magnet frame 3. Frame 3 is secured to an insulating panel t and core member 2 is provided with an elongated pole shoe 5 for attracting a pair of contact carrying armatures which extend in tures i are attracted into engagement with a non-magnetic stop 9 secured to the outer end of magnet frame arm 3" against the action of their asociated springs I, and said springs may be 361- justedto provide forreleaseofsaidarmaim'esat different current values in coil I.

Thearmatureiillustratedinlflglmsnormally closed contacts II and II asociated therewith. Contact I! is fixed toan L-shapedbraaket l2 whichinturnissecuredtoaninsulatinghlock l3 mounted upon magnet frame arm 3". Bracket I2 is electrically connectedby a lead ll to a binding post i5 mounted upon base l.

Contact ll ismounted upononeendofafinger i6 and said finger is grooved adjacent its opposite end to provide a transverse bearing portion ll of convex shape on the rear face thereof. Armature Ghasahearlngplate ilfiaedtothe front face thereof by screws I! and as illustrated inFigs. 3 and isaidplateisprovidedwithaslot 29 having bearing projections 2l--2l formed on opposite sides thereof for receiving the bearing portion ll of finger ii. Thebearing portion ll of finger i6 is provided with an opening for receiving apin 2i whichisfixedtoarmatureianddlsposed at right angles thereto. Pin 2| carries an elongated sleeve 22 which is slidahle thereon and is provided with a flange projection 23 for engaging the front face of contact finger It at points on opposite sides of the bearing portion l'l. Sleeve 22 is pressed against the front face of contact finger i6 by a coil spring 24 heldimder compression between the flange 23 of said sleeve and a cup washer 25 secured to the outer end of pin 2i by a cotter pin 26. Bearingplate ll has apin 21 fixed thereto which extends through an opening in finger ii to hold said finger against lateral movement with respect to armature 5. Finger ii is electrically connected to bracket I by a flexible pigtail connection 28.

As is apparent from the foregoing, spring it acts through the medium of sleeve 22 to hold the bearing portion ll of finger il in engaganent with the bearing projections "-2! on hearing plate ll. 'Also as is apparent from Fig. 4, the flange 23 on sleeve 22 engages the outer face of finger It to yieldingly hold said finger in parallel relation with respect to the front face of armature 8, as shown in Pig. 4.

When armature 6 is released from its attracted position contact ii is moved into engagement with contact ll under the action of spring 2 to establish circuit between bracket I and binding post i5. Upon engagement of said contacts finger l6 yields against the biasing action of its associated spring 24, as shown in Fig. 1, to permit overtravel of armature i with respect to said finger by inertia of the moving switch parts. During this overtravel of armature 5, bearing portion ll of contact finger It is rocked with respect to its associated bearing projection 2l-2l and sleeve 22 is moved outwardly upon its associated pin 2i against the action of spring 2|. Thus upon overtravel'of armature, 5 part of the kinetic energy present in the moving switch parts is stored in spring 24 and the remainder is dissipated by frictional losses which occur between bearing portion l1 and bearing projections 202ll between finger and sleeve 22 and between said sleeve and the pin 2i. These frictional losses are of relatively large value, and when overtravel of armature 6 is stopped the energy stored in spring 24 is barely sufiicient to restore finger IE to normal position with respect to said armature when the latter is again moved into its attracted position. In practice it has been found that frictional dissipation of a large part of the energy present in the moving switch parts during overtravel of armature 6 beyond the position shown in Fig. 1 tends to minimize rebound of contact Ii when the same is moved into engagement with contact "I.

What I claim as new and desire to secure by Letters Patent is:

1. In an electric switch, in combination, a movable operating member' biased to move in one direction, a contact finger fulcrumed at one end upon said operating member, a stationary contact to be engaged by the opposite end of said finger upon biased movement of said operating member into a given position, and a spring pressure device associated with said finger at its fulcrum point, including a supporting pin fixed to said operating member and extending through an opening in said finger at its fulcrum point, a compression spring carried by said pin, a sleeve slidable on said pin and held in engagement with said finger under the action of said spring to normally hold, said finger and said operating member in a given angular relation when said finger is disengaged from said stationary contact and to permit inertial overtravel of said operating member beyond said given position upon movement of said finger into engagement with said stationary contact, said sleeve and the fulcrum connection between said operating member and said finger acting during overtravel of said operating member to eifect frictional dissipation of the energy present in said operating mem- 7 her and said finger at a rate to minimize rebound of said finger when the same is moved into engagement with said stationary contact.

2. In an electric switch, in combination, a movable operating member biased to move in one direction, a contact finger supported at one end upon said operating member by an open pivotal bearing, a stationary contact to be engaged by the opposite end of said finger upon biased movement of said operating member into a given position, a spring device associated with' said finger at its bearing point to hold the same in assembled position upon said operating member, said device including a supporting pin fixed to said operating member and extending through an opening in said finger at its bearing point, a com pression spring carried by said pin and a sleeve slidable on said pin and held in engagement with said finger under the action of said spring tosubject said finger to a biasing force which normally holds the same in a given angular position with respect to said operating member, said sleeve being movable upon said pin against the action of said spring to permit inertial overtravel of said operating member beyondsaid given position when said finger engages said stationary contact and said open pivotal bearing and said sleeve acting during such overtravel of said operating member to eiiect frictional dissipation of energy present in said operating member and said finger at a rate to minimize rebound of said finger when the same is moved into engagement with said stationary contact.

8. In combination, a stationary contact, a cooperatingcontact finger, a movable supporting and actuating member for said finger and a connection between said finger and said member comprising a bearing portion on said-finger and cooperating bearing projections on said member arranged for sliding engagement with said bearing portion and further comprising spring pressure means carried by said movable member and bearing upon said finger at said bearing portion with balanced forces, to effect a highly frictional connection between said bearing portion and its cooperating bearing projections and also to rock said finger into relationship with said supporting and actuating member such as to provide a play therebetween to be taken up against the bias of said spring pressure means when said member is operated for engagement of said finger with said stationary contact, said spring pressure means being positioned so that the major portion of its pressure is used to eiiect friction in the connection between said finger and said movable member and so that only asmali amount of its pressure is used in rocking said finger into relationship with 7 said movable member, and said spring pressure means comprising parts afiording high frictional resistance to take-up of such play between said finger and said member thereby to minimize tendency of rebound of said finger upon engagement with said stationary contact.

4. In an electric switch having a stationary contact, a cooperating contact finger and a movable supporting and actuating member for said contact finger, a connection between said member and said finger comprising a bearing surface on said movable member, a cooperating bearing portion on said finger arranged for sliding engagement with said bearing surface, and spring pressure means carried by said movable member and engaging said finger concentrically with said bearing portion in manner that the major part of the energy of said spring pressure means will be used to eifect highly frictional resistance in said connection and only a small part of said energy will be used to return said finger to normal position with respect to said movable member when not in engagement with said stationary contact, said spring pressure means itself comprising relatively movable parts having high frictional resistance to their relative movement.

MERLE R. SWINEHART.

REFERENCES CITED I The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,499,421 StOekle July 1, 1924 2,092,478 Sommermeyer Sept. 7, 1937 2,158,841 Stevens May 16, 1939 2,184,767 Schaelchlin Dec. 26, 1939 2,275,924 Seeley Mar. 10, 1942 2,292,497 Vradenburgh Aug. 11, 1942 

